Yens improvement to Bellman-Ford Suppose that we order the edge relaxations in each pass of the Bellman-Ford algorithm as follows. Before the first pass, we assign an arbitrary linear order 1; 2;:::;jV j to the vertices of the input graph G D .V; E/. Then, we partition the edge set E into Ef [ Eb, where Ef D f.i; j / 2 E W ij g. (Assume that G contains no self-loops, so that every edge is in either Ef or Eb.) Define Gf D .V; Ef / and Gb D .V; Eb/. a. Prove that Gf is acyclic with topological sort h1; 2;:::;jV ji and that Gb is acyclic with topological sort hjV j; jV j1;:::;1i. Suppose that we implement each pass of the Bellman-Ford algorithm in the following way. We visit each vertex in the order 1; 2;:::;jV j, relaxing edges of Ef that leave the vertex. We then visit each vertex in the order jV j; jV j1;:::;1, relaxing edges of Eb that leave the vertex. b. Prove that with this scheme, if G contains no negative-weight cycles that are reachable from the source vertex s, then after only djV j =2e passes over the edges, :d D .s; / for all vertices 2 V . c. Does this scheme improve the asymptotic running time of the Bellman-Ford algorithm?
2/29/2016 Cognitive Task Analysis o Methods for decomposing job & task performance into discrete, measurable units with special emphasis on eliciting mental processes & knowledge content o Think-aloud protocol Approach that investigates thought processes of experts who achieve high levels of performance o Time consuming & requires a good deal of expertise to do well o Consider the following to determine whether cognitive task analysis may be worthwhile: Persistent performance problems Costly errors or accidents Training difficult to transfer to job behavior Takes a long time to achieve high levels of performance New Addition of Job Analysis Instruments o Personality-Related Position Requirements Form (PPRF) Devoted to identifying personality predictors of job performance Intended to supplement job analysis Summary of Job Analysis Process o The more information gathered from the greatest number of sources, the better the job analyst can understand the job o Most job analyses should include considerations of personality demands & work context Occupational Information Network of O*NET o Introduced by federal government to replace the Dictionary of Occupational Titles (D.O.T.) o Electronic medium, so it can be updated instantaneously as changes occur Competency Modeling o Identifies characteristics desired across all individuals & jobs within an organization o Connects individuals with organizational viability & profitability o Natural extension of job analysis logic, rather than a replacement Job Evaluation, Comparable Worth, & the Law o Job evaluation: Method for making internal pay decisions by comparing job titles to one another & determining their relative merit o Compensable factors o Skills, responsibility, effort, & working conditions o Equal Pay Act of 1963: requires “equal pay for equal work.” Comparable Worth o Notion that people who are performing jobs of comparable worth to an organization should receive comparable pay o In the end, comparable worth is concerned with the social value of fairness Job Analysis & Employment Litigation o Competent job analysis does not guarantee validity, but absence of credible job analysis could be very damaging o Growing gap between evolution of I-O psychology & Uniform Guidelines on Employee Selection Procedures (1978) o SIOP Principles (2003) are more updated and consistent with current research Chapter 5—Performance Measurement Basic Concepts in Performance Measurement o Uses for performance information Criterion data Employee development Motivation/satisfaction Rewards Promotion Layoff Types of Performance Data o Objective o Personnel o Judgmental Performance Measurement o Relationships among performance measures o Hands-on performance measures Employee engages in work-related tasks Include carefully constructed simulations Walk-through testing Employee describes in detail how to do a job o Electronic performance monitoring Commercial Driving Fleets Improving Performance Computer Usage at Work Worker Attitudes What steps should employers take to improve attitudes Performance Management o Emphasizes link between individual behavior & organizational strategies & goals o 3 Components of Performance Management Definition of performance Actual measurement process Communication between supervisor & subordinate about individual behavior & organ. expectations Perceptions of Fairness in Performance Measurement o Factors associated with fairness measurement Appraisal frequency positively related to fairness perceptions Joint planning with supervisor to eliminate weaknesses enhances fairness perception Supervisor’s knowledge of duties of person being measured Supervisor’s knowledge of actual performance of person being rated o Distributive justice Fairness of outcomes related to decisions You get something as a result of your behavior; i.e. promotion, bonus, fired o Procedural justice Fairness of process by which ratings are assigned & a decision is made Is the process fair o Interpersonal justice Respectfulness & personal tone of communications surrounding evaluation 3/2/2016 Performance Rating—Substance o Theories of performance rating Process model—who rates who Addresses various factors comprising rating process Content model—what is being rated and how it is rated Addresses content input to supervisory ratings Rating context—why is it being rated Includes both announced purpose & other, non- announced agendas surrounding ratings Need to be aware of the different reasons authorities have Focus on Performance Ratings o Overall performance ratings Provide a number to describe how you perform different tasks in relation to contextual performance and counter- productive performance; this helps compare two people Influenced by 3 factors Task performance Contextual performance/OCB Counter-productive performance Performance Ratings o Trait ratings – a warning; rates aspects of personality E.g. I am aloof, abrasive Can’t be fired just off of trait ratings; can’t change personality o Task-based ratings Effectiveness of employee in accomplishing duties Most easily defended in court; can be fired because of this o Critical incidents method Examples of critical behaviors that influence performance i.e. how one goes about getting robbed in the bank; behaviors o Structural characteristics of performance rating scale Extent to which duty/characteristic being rated is behaviorally defined (should not be defined by personality!!) Extent to which meaning of response categories is defined Degree that person interpreting ratings can understand response that rater intended Rating Formats o Graphic rating scales (most common) Graphically display performance scores running from high to low o Checklist List of behaviors presented to rater who places a check next to items that best (or least) describe the ratee o Weighted checklist Included items have assigned values or weights; can have fractured ratings o Forced-Choice Format Requires the rater to choose two statements out of four that could describe the ratee o Behaviorally anchored rating scales (BARS) Rating format that includes behavioral anchors describing what worker has done, or might be expected to do, in a particular duty area 3/4/2016 Employee Comparison Methods o Involve direct comparison of 1 person w/another o Simple ranking Employees ranked from top to bottom according to assessed proficiency o Paired comparison Each employee in a group is compared with each other individual in the group o Useful in making layoff or downsizing decisions o Feedback is difficult because there is no clear standard of performance o Difficulty in comparing individuals in different groups Performance Rating—Process o Rating sources Supervisors Most common information source Many actively avoid evaluation & feedback Peers More likely to know about a worker’s typical performance Conflict of interest likely when competing for fixed resources Self-Ratings o Discussion of ratings with supervisor increases perceptions of procedural fairness o Potential for distortion & inaccuracy Minimized with supervisor discussion o Conflict of interest if used for administrative purposes Rating Sources o Subordinate ratings Critical that subordinate feedback be kept anonymous o Customer & supplier ratings Important from business strategy vantage point o 360 degree systems Collect & provide an employee with feedback that comes from many sources Often used for feedback & employee development Rating Distortions o Central tendency error Raters choose mid-point on scale to describe performance when more extreme point is more appropriate o Leniency-severity error Raters are unusually easy or harsh in their ratings o Halo error Same rating is assigned to an individual on a series of dimensions, causing the ratings all to be similar; lack of identification of strengths and weaknesses A “halo” surrounds the ratings Rater Training o Some distortions (errors) may be corrected through training o Administrative training Important for uncommon rating systems (e.g., BARS) or if 1 or more structural characteristics are deficient o Psychometric training Makes raters aware of common rating errors in hopes of reducing such errors Framer of Reference Training o Based on assumption that rater needs context for providing rating Basic steps Provide information about multidimensional nature of performance Ensure raters understand meaning of scale anchors Engage in practice rating exercises of standard performance Provide feedback on practice exercise Reliability & Validity of Performance Rating o Reliability Currently the subject of lively debate Inter-rater reliability considered poor but this isn’t necessarily bad considering each rater relies on a different perspective o Validity Depends on manner by which rating scales were conceived & developed